The OCD You Can’t See: Understanding the Mental Compulsions of Pure O
When people think of obsessive-compulsive disorder (OCD), they often picture compulsions they can see, like handwashing, checking, counting, or arranging. But not all compulsions are visible. For some people with OCD, the distress and rituals live entirely in the mind.
Purely obsessional OCD, often called Pure O, is marked by intrusive thoughts and mental compulsions that can be just as exhausting and disruptive as physical ones. Because there’s no obvious behavior, it’s easy for others to overlook. But that doesn’t mean it’s less serious.
This month, we’re continuing our focus on lesser-known forms of OCD with a closer look at Pure O. If you missed our recent piece on Relationship OCD, you can read it here.
What Is Pure O?
Purely obsessional OCD (commonly known as Pure O) is a subtype of OCD characterized by intrusive, distressing thoughts without visible compulsions. But the name is misleading. People with Pure O do engage in compulsions; they’re just internal. Mental rituals like rumination, reassurance-seeking, “undoing” behaviors, or attempts to neutralize thoughts with mental prayers, counting, or silent reasoning are common. These aren’t quirks or personality traits. They’re part of the OCD cycle and can be just as disruptive as more recognizable behaviors like checking or cleaning.
As noted in a clinical review by Williams et al. (2011), these internal compulsions are often missed in traditional assessments, despite being just as impairing as overt rituals. Pure O is often missed or misunderstood because it doesn’t look like what most people imagine when they think of OCD. This can lead to misdiagnosis, delayed treatment, and an increased sense of shame or confusion for the person experiencing it.
When Compulsions Are Invisible
Many people associate OCD with visible rituals: checking locks, washing hands, and organizing items. But when the compulsions are internal—replaying conversations, analyzing thoughts, repeating prayers—others often miss the extent of distress involved. This is one of the reasons Pure O can be so misunderstood. It’s not that these individuals don’t have compulsions; it’s that their compulsions happen in silence.
Mental compulsions can include:
Repetitive thought-checking or scanning for reassurance
Mental reviewing or replaying of events
Silent counting, praying, or “canceling out” distressing thoughts
Rationalizing or arguing with the thought
For someone with Pure O, the urge to “figure out” or neutralize a disturbing thought becomes all-consuming.
Pure O in the Context of Eating Disorders
In clinical settings, it’s common to see obsessive-compulsive disorder overlap with eating disorders. But Pure O often adds an extra layer of complexity. For example, a client may engage in a food-related exposure, such as eating a fear food, but then silently ruminate about the calories or mentally plan excessive exercise to make up for it. These rituals aren’t visible, but they are compulsions nonetheless.
Mental compulsions in this context might look like:
Repeatedly calculating or trying to estimate caloric intake
Planning future restriction or exercise in response to eating
Mentally “undoing” a feared behavior or thought
Praying or engaging in magical thinking to prevent feared outcomes
This internal distress can be just as intense as the physical rituals often associated with OCD. When someone is working to recover from an eating disorder, these invisible compulsions can quietly maintain fear, rigidity, and avoidance.
What Treatment Must Address
Effective OCD treatment has to go beyond recognizing intrusive thoughts. It must address the internal strategies people use to neutralize, rationalize, or control those thoughts. Without this step, therapy becomes another form of reassurance or avoidance.
Exposure and Response Prevention (ERP) remains the gold standard for OCD, and with Pure O, the work often centers on resisting mental rituals. This might mean noticing the urge to replay a thought, resist the need to mentally “undo” something, or practice not assigning meaning to every passing image or impulse. It also requires naming those rituals for what they are: compulsions.
At Nourished Minds, we frequently support clients navigating this exact process, many of whom didn’t realize they were engaging in compulsions at all. One of the most common internal rituals we see is rumination, a repetitive mental loop that can feel involuntary and exhausting. For more on this, see our earlier blog on how to stop ruminating thoughts.
Getting Help for Pure O
Pure O is real. It’s treatable. And it’s more common than most people realize. If you’re experiencing intrusive thoughts and feel stuck in a loop of mental checking, reviewing, or reassurance, it may be time to consider whether OCD is playing a role. A skilled clinician will never dismiss your experience just because they can’t see it.
You don’t have to explain every thought. But you deserve a provider who knows how to listen between the lines.